{-|
Library csound-expression allows csound code construction
in functional way.
It has two parts "CsoundExpr.Base" and "CsoundExpr.Opcodes".
First part "Csound.Base" contains essential functionality of the package.
Second part "Csound.Opcodes" contains opcode definitions.
This module provides overview of the library.
For examples see sources, folder 'examples'
-}moduleCsoundExpr(-- * Introduction{-|
Csound-expression is csound code generator. Program
produces value of 'CsoundFile' type.
'CsoundFile' is 'Show'. So that is the way to get csound code.
Function 'csd' can be invoked to make value of 'CsoundFile' type.
>csd :: Flags -> Header -> EventList Dur SignalOut -> CsoundFile
* 'Flags' is 'String'. It's pasted in place of csounds flags.
* 'Header' is csound header declaration.
See module "CsoundExpr.Base.Header" for more details.
* 'EventList' represents csound orchestra and score sections. This
type comes from external library 'temporal-media' [1].
'EventList' contains values with time marks.
Value begins at some time and lasts for some time.
Very much like csound notes, but there is one difference
no need for p-field parameters, translator derives them from
note structure encoded in values of type 'SignalOut'.
'EventList' can be constructed directly with functions of
'temporal-media' library, but better way is to use some
front-end. Package 'temporal-music-notation' [2]
provides higher level musical functionality for 'EventList'
construction.
\[1\] <http://hackage.haskell.org/package/temporal-media>
\[2\] <http://hackage.haskell.org/package/temporal-music-notation>
-}-- * Instruments{-|
Instruments are functions from some signal representation to signal.
'Score' (from 'temporal-music-notation' library) or
'EventList' (from 'temporal-media' library) is a 'Functor',
so to play on instrument means to apply instrument.
to container of its notes. Instrument can be made with opcodes.
Translator derives p-fields from instrument structure. There are only
two explicit p-fields 'itime' and 'idur' (@p2@ and @p3@ in csound).
-}-- * Signals / Types{-|
Signals are represented with trees. Tree contains information about how
signal was build.
There are five types for signals ("CsoundExpr.Base.Types").
'Arate' is audio rate signal
'Krate' is control rate signal
'Irate' is init value
'SignalOut' is no output at all (it's produced by opcodes
like out, outs, xtratim)
'BoolRate' is comparision of two control or init rate signals
("CsoundExpr.Base.Boolean")
There are two classes to allow csound's polymorphism : 'X' and 'K'
'X' = 'Arate' | 'Krate' | 'Irate'
'K' = 'Krate' | 'Irate'
Csound's S - signal is represented with 'String'.
Ftable is represented with 'Irate'. If you want to get 'Krate' ftable
you can construct it with function 'ifB'.
There are two special types 'MultiOut'
(for opcodes that may produce several outputs,
see "CsoundExpr.Base.MultiOut")
and 'SideEffect'
(for opcodes that rely on number of appearances in csound code,
like @unirand@, see "CsoundExpr.Base.SideEffect")
-}-- * Opcodes {-|
Naming conventions : Opcodes are named after csound's
counterparts usually. Some opcodes in csound can produce
signals of different rates by request (oscil, linseg).
Those opcodes are labelled with suffix. Suffix defines
output rate of signal (oscilA, oscilK). Some opcodes
in csound have unfixed number of inputs due to setup
parameters, almost all of them. Those opcodes have
first argument that is list of setup parameters.
example
>oscilA :: (X a, X b) => [Irate] -> a -> b -> Irate -> Arate
>oscilK :: (K a, K b) => [Irate] -> a -> b -> Irate -> Krate
-}-- * Imperative style csound code{-|
Most of csound opcodes can be used in functional way.
You can plug them in one another, and make expressions,
but some of them behave like procedures and rely on order
of execution in instrument. Module "CsoundExpr.Base.Imperative"
provides functions to write imperative csound code.
'outList' - to sequence procedures
'(/<=/>)' - Assignment
'ar', 'kr', 'ir', 'gar', 'gkr', 'gir' - named values,
to produce signal with specified name and rate.
Functional style :
>exmpInstr :: Irate -> SignalOut
>exmpInstr pch = out $ oscilA [] (num 1000) (cpspch pch) $
> gen10 4096 [1]
Imperative style :
>exmpImper :: Irate -> SignalOut
>exmpImper pch = outList [
> ir "amp" <=> num 1000,
> ir "cps" <=> cpspch pch,
> ir "ft" <=> gen10 4096 [1],
> ar "sig" <=> oscilA [] (ir "amp") (ir "cps") (ir "ft"),
> out (ar "sig")]
-}-- * Arithmetic{-|
You can use polymorphic operations to do some arihmetic
on signals from "CsoundExpr.Base.Arithmetic". And Signal
is 'Num'. 'Eq' is undefined though.
-}-- * Preview{-|
To see what will come out of an expression you can
print it. 'Arate', 'Krate' and 'Irate' are 'Show'.
-}-- * User Defined opcodes{-|
You can add your own opcodes to library,
see "CsoundExpr.Base.UserDefined"
-}-- * MIDI {-|
There are two ways to tell 'csd' to include instrument
in csound file. Instrument can be a part of 'Score' or
it can be midi instrument, then it should be mentioned
in 'massign' or 'pgmassign' function. If you want to
play midi-instr for some time @t@, you can tell it
to 'csd' function by invoking 'csd' with @'none' t@
('temporal-media') or @(toList $ 'rest' t)@ ('temporal-music-notation')
in place of 'EventList' value.
Csound statement @f 0 n@ is always present in generated .csd file.
Here @n@ is score's duration.
>import Temporal.Music
>
>import CsoundExpr
>import CsoundExpr.Opcodes
>
>flags = "-odac -d -+rtmidi=virtual -M0"
>
>header = [massign [] 1 instrMidi]
>
>instrMidi :: SignalOut
>instrMidi = out $ oscilA [] (num 5000) cpsmidi $ gen10 4096 [1]
>
>res = csd flags header (rest 3600)
>
>-- play: requires tmp folder in current directory
>main = do
> playDac "tmp" "new" res
-}-- * Limits-- ** What can not be expressed -- *** ids{-|
The major benefit and major problem of csound-expression is
abscense of ids for p-fields, ftables, notes and instruments.
no ids for ... means ... no
p-fields/notes - opcodes that rely on p-fields or invoke instruments
ftables - k-rate ftables
instruments - convenient way to specify order of instruments
-}-- *** imperative program flow control-- | There is no program flow control opcodes (like if, then, goto).-- But you can use functional if/then from module -- "CsoundExpr.Base.Boolean"-- *** Srate-- | I've decided to represent csound's S-rate with 'String'.-- Signal is represented with tree and it means i can't include-- opcodes that produce Srate-- ** Hack-way around (what somehow can be expressed)-- *** instrument order{-|
Orchestra section is generated from 'EventList'. Different instruments
have different tree structure and one instrument's tree can't be
transformed into another one by replacing leaf-values only.
You can point to instrument by its structure. There is opcode in
"CsoundExpr.Base.Header" that specifies order of instruments by
list of notes. 'instrOrder' takes in list of notes, if instrument's
tree is equivalent to note it is placed in relation to list of notes.
There are ways to make mistake. Sometimes it's unpredictable.
In example below
@q1 =/= q2@
@sco@ contains two instruments (one with @x@, and another
one with @cpspch x@)
>
>osc x = oscilA [] (num 1000) x $ gen10 4096 [1]
>env = lineK 1 idur 0
>
>q1 x = osc x <*> env
>q2 x = env <*> osc x
>
>sco1 = note 1 440
>sco2 = note 1 $ cpspch 8.00
>
>sco = fmap q1 $ sco1 +:+ sco2
I think maybe it's worthwhile to introduce some way of instrument id
assignment.
-}moduleCsoundExpr.Base)whereimportCsoundExpr.Base